Lubricant



Patented Dec. 15, 1942 ration of Indiana cam, 11]., lssignor to Chicago, 111., a corpo- No Drawing. Application September 20, 1940.

Serial No. 358,429

Claims. (Cl. 252-53) This invention relates to improvements in lubricants and particularly to lubricants oi the type of motor oils.

It is an object of the present invention to provide an improved motor oil having favorable temperature viscosity characteristics and greatly improved engine wear properties.

It is a further object of the invention to provide a motor oil having favorable stability, minimum resin, varnish and/or carbon formation.

A still further object of theinvention is to provide a motor oil having, in addition to the foregoing advantages, excellent consumption characteristics.

I have discovered that a motor oil providing the above desired characteristics can be obtained by blending a narrow cut mineral lubricating oil,

preferably a narrow cut solvent extracted mineral lubricating oil, and a synthetic lubricating oil of the type hereinafter described.

The narrow cut mineral lubricating oil is preferably a raffinate of a solvent extracted mixed base petroleum distillate which is distilled to produce a relatively narrow cut fraction. The raffinate may be obtained by any ofthe well-known solvent extraction processes, such as the furfural process, the phenol process, the sulfur dioxide process. the sulfur dioxide-benzol process, the nitro benzene process, the nitro benzene-sulfuric acid process or the Chlorex process.

In preparing the motor oils of the various grades it is the usual practice to prepare base oils of the S. A. E. grade and of the S. A. E. grade which are then blended in the proper proportions to produce intermediate grades of oils. In preparing the base oils in accordance with the present invention the solvent extracted distillate is distilled, preferably under reduced pressure, to remove both the light ends and the heavier ends of the fraction, the distillation being carried out so that the initial boilingpoint under 1 millimeter mercury pressure is at least about 400 F. and the difference in temperature between the initial distillation temperature at 1 millimeter mercury pressure and the temperature at which distills under 1 millimeter mercury pressure is not grater than about 200 F. and preferably not greater than about 185 F. The term "narrow cut as used herein-and in the appended claims refers to distillates in which the differ- Tl ence between the initial distillation temperature and the distillation temperature at the 90% point, both at '1 millimeter. mercury pressure is not greater than about 200 F. The 90% distillation temperature referred to herein is a measure of the tendency of lubricating oils to form carbon in internal combustion engines, and is.

determined by distilling a 200 cubic centimeter sample of the oil at 1 millimeter mercury pressure and dete the .temperature of the vapor when 90% has distilled. The test is described in detail by W. H. Bahlke et .al. in the S. A. E. Journal, vol. 29, 1931 (page 215). This 90% distillation point is also referred to as the 'Carbonization Index of the oil.

The elimination of thelighter and less volatile components of the rafllnate oil effects a considerable improvement in oil consumption while the I removal of heavier fractions from-the raiiinate reduces the combustion chamber carbon formation to a large degree, and furthermore, such carbon as is formed by a narrow cut raflinate oil is softer and more easily removed and is thus less liable to cause scratching ofrthe piston rings,

cylinder bores and the like of the engine.

Illustrative of suitable base oils of the improved motor oils prepared in accordance with the present invention are the 20 S, A. E. and the 50 S. A. E. oils having the following inspections:

2) SAE 50 SAE Gravity. A. P. I--. 28.3 26 8 Flash, F 415 510 Pour point, F -5 Saybolt viscosity at F 382 1482 Saybolt viscosity at 210 F 56. 4. l0 Viscosity index 93 8 Carbonization index,v F 535 Initial distillation temperature, F. 400 470 1 At I'm. m. of mercury absolute pressure.

The above oils are rafllnates of Ghlorex extracted distillatesof a Mid-Continent crude oil.

The synthetic lubricating oil is preferably one obtained by polymerizing, in the liquid phase, an iso-mono-olefin such as isobutylene or a hydrocarbon mixture containing the same at a temperature of from about 0 F. to about 100 F. preferably at 32 F.'in the presence of a catalyst such as boron fluoride, aluminum chloride, zinc chloride or other similar active halide catalyst of the type employed in the Friedel-Crafts reaction. I may also employ the co-polymers of isomono-olefins with normal olefins. In the preparation of the polymers I may employ, for example, liquid isobutylene or a hydrocarbon mixture containing the same such as a butane-butylene fraction recovered from petroleum gases, especially those gases produced in the cracking of petroleum oils for the manufacture ofgasoline. This light fraction in contain from about 10% to about 25% isobutylene, the remainder bein al butane. The byprincipally butenes and norm k drocarbon mixture containing 10% to 25% isobutylene is maintained under pressure sufllcient to keep it in the liquid phase and cooled by suitable means to a temperature of for example. about 32 F. and from about 1 6% to about 2% boron fluoride based upon the isobutylene content of the material treated added with vigorous agitation. Excessive rise in temperature due to the heat of the reaction may be avoided by ef-- ficlent cooling. After the polymerization of the isobutylene, together with a relatively minor amount of the normal oleiins present, the reaction mass is neutralize and washed free of the acidic substances arising from the catalysts, the oily layer separated, and the polymer subsequently segregated from the unreacted hydrocarbons by distillation. mixture so obtained depending temperature of the reaction varies in consistency from a light liquid to a viscous oil-like material and contains polymers having molecular weights ranging from about 100 to 1500. The polymer so obtained is then vacuum distilled to remove the lighter and heavier fractions therefrom and to produce a final product having a Saybolt viscosity at 210 F. of about 185 seconds to 500 seconds and a flash point of about 350 F. to about 440 F.

In accordance with the present invention an improved motor oil is obtained by blending a narrow cut raflinate oil with from about 1% to about 40% and preferably from about 3% to about 20% .of an olefin polymer of the type described. To the blend I may add a small amount, 0.05% to 0.5%, of an anti-wear agent such as tributyl phosphite, diamyl sulfone, tributylphosphate, methyl dichloro stearate, etc. Blends of this composition show improved resistance to oxidation, substantially reduce varnish formation in internal combustion engines, and markedly reduce engine wear.

In the following tables are presented data of various tests employing blends of a narrow cut raiiinate oil and various concentrations of an isobutylene polymer. The control oil in each of these tests is a narrow cut raiilnate having the following specifications:

Gravity degrees A. P. I 28.3 Flash degrees F..... 415 Pour point do.... -5 Saybolt viscosity at 100 F seconds 382 Saybolt viscosity at 210 F do 56.4 Viscosity index 93 Carbonization index "degrees F 535' (at 1 m. m. of mercury degrees F Initial boiling point absolute pressure) The 'isobutylene polymer used in the blends had the following characteristics:

Gravity degrees A. P. L--- 32.! Flash degrees F 365 Pour point do --35 Saybolt viscosity at 100 seconds 469 Saybolt viscosity at 210 Fl do.. 58 Viscosity index 75 Carbonization index degrees FL... 470

The sludging time data of various blends of narrow cut rafilnate oil and isobutylene polymers are tabulated in ble 1. The sludging'time is the number of hours required for the samples to form milligrams and 100 milligrams of sludge when maintained at a temperature of about 341 F.\while air is being bubbled therethrough.

\ Table 1 Sludgi'ng time (hrs.)

Sample 10 milli- 1(1) milligrams grams (1) Control (narrow cut raiilnate) 81 140 (2) 1) +3% isobutylcne polymer M0 166 (3) l;+5% isobutylcne polymer..- 110 176 (4) El +10% isobutylene p0lymer I 210 (5) 1) +15% isobutylene polymer. 200-240 299-240 (6) (l)+20% isobutylene polymer. 300+ 300+ (7) (1) +50% isobutylene polymer. 300+ 303+ shown by the data presented in Table II. Also in Table II, in parenthesis, are tabulated the viscosity indices of the control oil and the blends for the corresponding oxidation periods. The viscosity indices in Table II are determined by the Dean and Davis method described in the Oil and Gas Journal of March 31, 1932, P88e 92.,

Table II Saybolt rdsoosity at 100 F. (seconds) after sample oxidation at 34l F. for- 9 hrs. 48 hrs. 96 his.

(I) i-Efiktfifiifif. 312 94.2) 409 (92.5 s49 71. 2) (2) Eil'i'ffiffiifiii 376 (92.8) 415 92. 4 521 11 a (3) Lfithiffiifff. an 92. a 411s (92.4) sec (at (4) ith 23 3 1 s31 91:0 419 90.0 497 (99 2 (5) 33 1 sea (90.3 V 420 (93.0 an (94:3 (6) 11 3 a? $23 3 3. 381- 91.9) 444 (etc 489 (99 a 1 1 +5o% isobutylone polymer 403 707 (81 Blends containing more than 50%0: isobutylene marked decrease in the viscosity index, whereas blends containing less than 50% of the polymer show little change in the viscosity index. It will be observed that after 96 hours of oxidation the control oil showed a substantial decrease in from about 10% to about 40% of the polymer showed only a very slight decrease in the viscosity index after oxidation for an equivalent period.

If desired other addition agents, such as pour point depressors, antioxidants, sludge dispersers and the like may I from the scope of the present invention as defined by the appended claims.

Iclaim:

1. An improved lubricant comprising a narrow cut solvent extracted petroleum oil having a distillation point under 1 millimeter mercury pressure not substantially greater than about 200 F. above the initial boiling point at 1 millimeter mercury pressure, and from about 1% to about 40% oi an isobutylene polymer having a polymer show a the viscosity index, but blends oi be added, without departing.

Saybolt viscosity at 210 F. of about 185 seconds to about 500 seconds and a flash point 01' about 350 1''. to about 450 F.

2. An improved motor oil comprising a solvent extracted petroleum point under. 1 millimeter mercury pressure not substantially greater than about 200 Ffabove the initial boiling point at 1 millimeter mercury pressure and from about'3% to about 20% of an isobutylene polymer having a Saybolt viscosity at 210 F. of from about 185 seconds to about 500 seconds.

3. An improved motor oil which is substantially resistant to oxidation, substantially non-varnish forming, and which has low consumption and carbon forming characteristics comprising a narrow cut solvent extracted petroleum oil having a 90% distillation point under -1 millimeter mercury pressure not greater than about 200 '1".

oil having a 90% distillation to about 500 seconds and a from about 1% above the initial boiling point at said pressure, to about 40% of an isobutylene polymer having a Saybolt viscosity at 210 F. of about 185 seconds to about 500 seconds and a small amount of an anti-wear agent.

4. vAn improved motor oil as described in claim 3 in which the anti-wear agent is tributyi phosphite.

5. An improved lubricant comprising a narrow cut solvent extracted petroleum oil having a 90%" distillation point under 1 millimeter mercury pressure not substantially greater than about 200 F. above the initial boiling point at 1 millimeter mercury pressure, and from about 1% to about 40% of an iso-mono-olefin polymer having a Saybolt viscosity at 210 F. of about 185 seconds flash point of about 350 F. to about 450 F.

EDWARD R. BARNARD. v 

